Numerical simulation on wave transmission in jointed rock masses

The propagation of seismic wave in a rock mass is not only affected by the mechanical properties of the intact rock but is also greatly influenced by the presence of joints in the rock masses which will significantly attenuate the propagating waves. In this paper, the transmission of plane wave with a waveform of single sinusoid cycle through a rock mass with joint(s) is investigated with the finite difference package FLAC2D. A joint is numerically modeled by an interface between two elastic rock bodies. It is found that the magnitude of interface stiffness governs the attenuation of the propagating wave across a single joint. The amount of attenuation is described by a transmitted coefficient ranged between 0 and 1. The relationship between the transmitted coefficient and (1) joint spacing between two parallel joints, (2) joint stiffness, and (3) dominant frequency of vibration is also studied. The results are compared to analytical solutions in literature and good matches are obtained. It is expected that the propagation of wave and thus vibrations in rock mass with more complicated geometry and geological features can then be investigated with the aid of the developed numerical model.